Sagittal Balance Systems And Methods Of Use Thereof

ABSTRACT

A system for dilating tissue includes a retractor having a pair of retractor blades that are movable towards and away from each other to retract tissue of a patient. The retractor blades have longitudinal guide channels. A first pin is attachable to a first vertebra. The system also includes an interbody spacer insertion device that has a guide channel for slidably engaging the longitudinal channel guide and is releasably attachable to an interbody spacer. The interbody spacer insertion device is configured to guide the interbody spacer into a space between adjacent vertebrae. A method for using the system includes advancing the retractor blades towards first and second vertebrae. The first retractor blade is attached to the first vertebra using the first pin and the retractor blades are moved away from each other. The interbody spacer insertion device is translated towards the vertebrae to position the interbody spacer between the vertebrae.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.16/156,600, filed on Oct. 10, 2018, the disclosure of which isincorporated herein by reference.

BACKGROUND Technical Field

The present disclosure relates generally to systems and methods forperforming lumbar surgical procedures.

Related Art

The human spine includes twenty-four vertebrae coupled sequentially toone another to form a spinal column that houses and protects criticalelements of the nervous system. Each vertebra has a cylindrical body(vertebral body), two pedicles extending from the vertebral body, alamina extending from the pedicles, two wing-like projections extendingfrom the pedicles, a spinous process extending from the lamina, a parsinterarticularis, two superior facets extending from the pedicles, andtwo inferior facets extending from the lamina. The vertebrae areseparated and cushioned by thin pads of tough, resilient fiber known asinter-vertebral discs that provide flexibility to the spine and absorbshock during physical activity.

A small opening (i.e., a foramen) located between each vertebra allowsfor passage of nerves through the vertebrae. However, when the vertebraeare not properly aligned (e.g., are offset or constricted), the nervesmay be compressed, leading to neurological disorders such as back pain,leg pain, numbness, tingling, diminished strength, a decrease in a rangeof motion of an individual, etc. Additionally, over time theintervertebral discs can deteriorate, tear, or herniate (where innerportions of the disc protrude through a tear), leading to constrictionand/or misalignment of the discs and vertebrae, again causing chronicpain, degenerative disc disease, or even tearing or herniation.

Surgical procedures were developed to correct these issues, includingprocedures that remove and replace damaged intervertebral discs withprosthetics. Initially, during these procedures, access to a compromiseddisc and the corresponding vertebrae is achieved by creating an incisionin a patient, guiding a retractor along a pathway to the target surgicalsite, and engaging the retractor to separate tissue between the initialincision and the target surgical site. After a partial or completeremoval of the damaged disc (commonly referred to as a discectomy), theresulting empty space between the corresponding vertebrae may collapseand/or become misaligned due to the partial or complete absence of thedisc. To prevent such collapse or misalignment clinicians may insert aprosthetic spacer between the vertebrae to maintain normal spacing andcurvature of the affected region. Once the prosthetic is secured, theretractor is removed, and the initial incision closed.

Accordingly, improved systems and methods for performing surgicalprocedures to replace damaged intervertebral discs are desirable.

SUMMARY

According to aspects of the present disclosure, a method for performinga surgical procedure may include advancing a pair of retractor blades ofa retractor toward a first vertebra and a second vertebra of a patient,fixing the retractor to the first vertebra with a first pin, moving theretractor blades away from each other, fixing the retractor to thesecond vertebra with a second pin, translating a distal portion of aninterbody spacer insertion device toward the vertebrae along alongitudinal guide channel of the retractor blade, positioning aninterbody spacer between the vertebrae of the patient, and disengagingthe interbody spacer from the interbody spacer insertion device.

In aspects of the present disclosure, translating the interbody spacerinsertion device may include translating an insertion guide along afixed trajectory toward a disc space of the patient.

According to aspects of the present disclosure, the interbody spacer maybe operably coupled to the interbody spacer insertion device.

In aspects of the present disclosure, operably coupling the interbodyspacer may include moving a first arm of the interbody spacer insertiondevice from a first position to a second position away from a second armof the interbody spacer, positioning the first arm about a plate, andmoving the first arm back to the first position to engage the plate. Theinterbody spacer may be coupled to the plate. The plate may be coupledto the interbody spacer via a screw configured to rotatably engage athreaded aperture of the interbody spacer. The screw may be rotated in afirst direction to release the screw from the interbody spacer. Forcemay be applied proximally to the interbody spacer insertion device toremove the interbody spacer insertion device from the patient.

According to aspects of the present disclosure, the first arm may bemoved from the first position to the second position to move the firstarm away from the second arm after removing the interbody spacerinsertion device. The plate may be decoupled from the interbody spacerinsertion device.

According to aspects of the present disclosure, a system for insertingan interbody spacer between vertebrae of a patient is disclosed. Thesystem includes a retractor having a first retractor blade and a secondretractor blade, the first and second retractor blades configured tomove away from each other to retract tissue of a patient, a first pinconfigured to be fixed to a first vertebra of a patient, and aninterbody spacer insertion device having a channel guide disposedthereon, the interbody spacer insertion device configured to slidablyengage the first retractor blade during insertion of an interbodyspacer. The first retractor blade may have a longitudinal guide channelconfigured to receive the channel guide of the interbody spacerinsertion device therein. The first retractor blade may be a caudalretractor blade, a cephalad retractor blade or an auxiliary retractorblade oriented medially or laterally.

According to aspects, the interbody spacer insertion device is coupledto the longitudinal guide channel of the first retractor blade andtranslatable along a fixed trajectory toward the first and secondvertebrae of the patient.

In aspects, the interbody spacer insertion device further includes afirst arm and a second arm disposed along a distal portion of theinterbody spacer insertion device, the first and second arms configuredto move between a first configuration and a second configuration. In thefirst configuration, the first and second arms of the interbody spacerinsertion device are approximated relative to one another, and in thesecond configuration, the first and second arms of the interbody spacerinsertion device are expanded relative to one another. The interbodyspacer insertion device may be configured to engage a plate coupled tothe interbody spacer. The plate may be coupled to the interbody spacervia a screw configured to rotatably engage a threaded aperture of theinterbody spacer.

According to aspects of the present disclosure, an expandable interbodyspacer includes a first body portion and a second body portion rotatablycoupled to the first body portion, such as via a rod, the first bodyportion having an engagement wall extending toward the second bodyportion. The expandable interbody spacer includes a pawl beam rotatablycoupled to the second body portion via a pawl rod, and a plurality ofteeth extending from the pawl beam. Transitioning the expandableinterbody spacer from a closed configuration to an open configurationmay cause the pawl beam to engage the plurality of teeth to prevent theexpandable interbody spacer from transitioning to the closedconfiguration.

In aspects of the present disclosure, a method of placing an expandableinterbody spacer includes advancing an expandable interbody spacercoupled to an interbody spacer insertion device toward vertebrae of apatient, the expandable interbody spacer maintained in a closedconfiguration by the expandable interbody spacer insertion device,positioning the expandable interbody spacer, in the closedconfiguration, between vertebrae of the patient, and releasing, with theinterbody spacer insertion device, the expandable interbody spacer. Uponrelease, the expandable interbody spacer is configured to transitiontoward an open configuration to match a natural lordosis of the patient.

According to aspects, advancing includes advancing the interbody spacerinsertion device along at least a portion of the longitudinal guidechannel of a retractor blade. Advancing may include aligning a channelguide of the interbody spacer insertion device to the longitudinal guidechannel of the retractor blade. The method may include moving or cuttingthe anterior longitudinal ligament (“ALL”) of the patient after theexpandable interbody spacer is positioned between and secured to thevertebrae, so that the expandable interbody spacer may be expanded orpermitted to expand after the ALL is released prior to expanding theexpandable interbody spacer.

In aspects of the present disclosure, a method of performing a surgicalprocedure is disclosed. The method may include advancing first andsecond of retractor blades of a retractor towards first and secondvertebrae of a patient, fixing the first retractor blade to the firstvertebra with a first pin, moving the first and second retractor bladesaway from each other, translating a distal portion of an interbodyspacer insertion device towards the first and second vertebrae with achannel guide associated with the insertion device traversing along alongitudinal guide channel of one of the first or second retractorblades, positioning an interbody spacer associated with the insertiondevice between the first and second vertebrae of the patient, anddisengaging the interbody spacer from the interbody spacer insertiondevice.

According to aspects, the second retractor blade may be fixed to thesecond vertebra with a second pin. The distal portion of the interbodyspacer may include translating the insertion device with an interbodyspacer/plate combination attached to the insertion device. The interbodyspacer/plate combination may include an interbody spacer and a plate,the interbody spacer may have an attachment screw receiving hole, theplate may have an attachment bore for receiving an attachment screwinserted therethrough to secure the plate to the interbody spacer.Translating the distal portion of the interbody spacer insertion devicemay include translating the distal portion of the interbody spacerinsertion device with the interbody spacer insertion device secured tothe plate and the plate secured to an interbody spacer. The plate maydefine an axis passing through the attachment bore, the plate may have apair of bone screw receiving holes with the center of each bone screwreceiving hole offset from the axis. Each bone screw receiving hole maybe offset from the axis on the same side of the axis. The center of eachbone screw receiving hole may be offset from the axis by an angle offrom about 5 degrees to about 30 degrees.

In aspects, the method may include inserting screws through the bonescrew receiving holes to secure the interbody spacer to the first andsecond vertebrae. Disengaging the interbody spacer insertion device mayinclude releasing the interbody spacer insertion device from the plate.The method may include removing the attachment screw from the plate andthe interbody spacer. Translating the distal portion of the interbodyspacer insertion device may include translating the distal portion ofthe interbody spacer insertion device with an expandable interbodyspacer associated with the distal portion of the interbody spacerinsertion device. Positioning the interbody spacer between the first andsecond vertebrae may include positioning the expandable interbody spacerbetween the first and second vertebrae in an unexpanded state.

According to aspects, screws may be inserted through bone screwreceiving holes of the expandable interbody spacer to secure theexpandable interbody spacer to the first and second vertebrae.

In aspects, the expandable interbody spacer may be released from theinterbody spacer insertion device.

According to aspects, an anterior longitudinal ligament may be releasedafter the expandable interbody spacer is secured to bone.

In aspects, the expandable interbody spacer may be expanded.

According to aspects, an auxiliary blade may be attached to theretractor.

In aspects, translating the distal portion of the interbody spacerinsertion device includes engaging a channel guide associated with thedistal portion of the interbody spacer insertion device with alongitudinal guide channel of the auxiliary blade and sliding thechannel guide in the longitudinal guide channel.

According to an aspect of the present disclosure, a system for insertingan interbody spacer between vertebrae of a patient is disclosed. Thesystem includes a retractor, a first pin, and an interbody spacerinsertion device. The retractor has a first retractor blade and a secondretractor blade, at least one of the first and second retractor bladeshas a longitudinal guide channel, the first and second retractor bladesconfigured to move away from each other to retract tissue of a patient.The first pin is configured to be fixed to a first vertebra of apatient. The interbody spacer insertion device includes a channel guidedisposed thereon, the channel guide configured to slidably engage thelongitudinal guide channel during insertion of an interbody spacer, theinterbody spacer insertion device configured to guide an interbodyspacer releasably attached thereto into a space between the first andsecond vertebrae based upon the sliding engagement of the channel guidewith the longitudinal guide channel.

In aspects, the interbody spacer insertion device is configured toreleasably couple to a plate, the plate securable to the interbodyspacer. The plate may have an attachment bore configured to receive anattachment screw to attach the plate to the interbody spacer. The platemay define an axis passing through the attachment bore, the plate mayhave a pair of bone screw receiving holes with the center of each bonescrew receiving hole offset from the axis. The center of each bone screwreceiving hole may be offset from the axis on the same side of the axis.The center of each bone screw receiving hole may be offset from the axisby an angle of from about 5 degrees to about 30 degrees.

According to aspects, the system may include an expandable interbodyspacer releasably secured to a distal portion of the interbody spacerinsertion device. The expandable interbody spacer may have an unexpandedstate and an expanded state. The expandable interbody spacer may definea pivot axis and a pair of bone screw receiving holes, the pair of bonescrew receiving holes being offset from a plane perpendicular to thepivot axis. The system may include an auxiliary blade securable to theretractor. The auxiliary blade may include a longitudinal guide channel,the channel guide being slidably engageable with the longitudinal guidechannel of the auxiliary blade.

In an aspect of the present disclosure, an expandable interbody spaceris disclosed. The expandable interbody spacer includes a first bodyportion and a second body portion, a pawl beam, and a plurality of teethextending from an engagement wall. The first body portion and the secondbody portion are pivotably coupled via a rod. Each of the first bodyportion and the second body portion defines a bone screw mount offsetfrom a plane perpendicular to the pivot axis defined by the rod. Eachbone screw mount includes a bone screw aperture. The pawl beam rotatablycouples to the second body portion via a pawl rod. The plurality ofteeth extending from the engagement wall is configured to engage thepawl beam. Transitioning the expandable interbody spacer from a closedconfiguration to an open configuration causes the pawl beam to engagethe plurality of teeth to prevent the expandable interbody spacer fromtransitioning towards the closed configuration.

In aspects of the present disclosure, a combination of a plate and aninterbody spacer includes an interbody spacer having an attachment screwreceiving hole, and a plate. The plate defines an attachment bore forreceiving an attachment screw inserted therethrough to secure the plateto the interbody spacer. The plate further defines an axis passingthrough the attachment bore and a pair of bone screw receiving holeswith a center of each bone screw receiving hole offset from the axis.

According to aspects, the combination further includes a screwconfigured to extend through the attachment bore and engage theattachment screw receiving hole to secure the plate to the interbodyspacer. The center of each bone screw receiving hole may be offset fromthe axis on the same side of the axis. The center of each bone screwreceiving hole may be offset from the axis by an angle of from about 5degrees to about 30 degrees.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate embodiments of the disclosure andtogether with a general description of the disclosure given above, andthe detailed description of the embodiment(s) given below, serve toexplain the principles of the present disclosure.

FIG. 1 is a perspective view of a retractor system provided inaccordance with the present disclosure;

FIG. 1A is a top plan view of a retractor of the retractor system ofFIG. 1;

FIG. 1B is a side, cross-sectional view of the retractor of FIG. 1Ataken along section line 1B-1B of FIG. 1A;

FIG. 1C is a side, cross-sectional view of the retractor system of FIG.1A taken along section line 1C-1C in FIG. 1A;

FIG. 2A is a top plan view of a retractor blade for use with theretractor of FIG. 1A;

FIG. 2B is a side plan view of the retractor blade of FIG. 2A;

FIG. 2C is a perspective view of an auxiliary blade for use with theretractor of FIG. 1A;

FIG. 2D is a perspective view of another embodiment of an auxiliaryblade of the present disclosure;

FIG. 2E is a side plan view of the auxiliary blade of FIG. 2D;

FIG. 3A is a side view of a dissector for use with the retractor systemof FIG. 1;

FIG. 3B is a cross-sectional view of the dissector of FIG. 3A;

FIG. 4A is a top plan view of a spinal interbody spacer for use with theretractor system of FIG. 1;

FIG. 4B is a side plan view of the spinal interbody spacer of FIG. 4A;

FIG. 4C is a cross-sectional view of the spinal interbody spacer of FIG.4A taken along section line 4C-4C of FIG. 4B;

FIG. 4D is a top plan view of an interbody spacer attachment plate foruse with the interbody spacer of FIG. 4A;

FIG. 5A is an exploded perspective view of an expandable interbodyspacer according to embodiments of the present disclosure;

FIG. 5B is a perspective view of the expandable interbody spacer of FIG.5A in a closed configuration;

FIG. 5C is an end view of the expandable interbody spacer of FIG. 5A inthe closed configuration;

FIG. 5D is a cross-sectional view of the expandable interbody spacer ofFIG. 5A in the closed configuration, taken along section line 5D-5D ofFIG. 5B;

FIG. 5E is a perspective view of the expandable interbody spacer of FIG.5A in an open configuration;

FIG. 5F is an end view of the expandable interbody spacer of FIG. 5A inthe open configuration;

FIG. 5G is a cross-sectional view of the expandable interbody spacer ofFIG. 5A in the open configuration, taken along section line 5G-5G ofFIG. 5E;

FIG. 6A is a side, plan view of an interbody spacer translation systemfor use with the retractor system of FIG. 1 or the retractor of FIG. 1A;

FIG. 6B is an exploded view of the distal portion of the interbodyspacer translation system of FIG. 6A;

FIG. 7 is a perspective view of interbody spacer translation system ofFIG. 6A engaging the retractor of FIG. 1A;

FIG. 8A is a perspective view of an expander provided in accordance withthe present disclosure;

FIG. 8B is a perspective view of the expander of FIG. 8A engaging anexpandable interbody spacer disposed between a first vertebra and asecond vertebra;

FIG. 8C is a perspective view of the expandable interbody spacerdisposed between the first and second vertebrae of FIG. 8B in a closedconfiguration;

FIG. 8D is a perspective view of the expandable interbody spacerdisposed between the first and second vertebrae of FIG. 8B in an openconfiguration; and

FIG. 9 is a flow diagram illustrating a method for retracting tissue andinstalling an interbody spacer between vertebrae of a patient.

DETAILED DESCRIPTION

Embodiments of the presently described retractor systems and methods aredescribed in detail with reference to the drawings, in which like orcorresponding reference numerals designate identical or correspondingelements in each of the several views.

Reference will now be made to terms used throughout the presentdisclosure to describe the principles of the present disclosure. As usedherein, the term “clinician” refers to a doctor, nurse, or other careproviders and may include support personnel. As is traditional, the term“distal” refers to structure that is, in use, positioned farther fromthe clinician, whereas the term “proximal” refers to structure that ispositioned closer to the clinician. Further, directional terms such asfront, rear, upper, lower, top, bottom, distal, proximal, and the likeare used to assist in understanding the description and are not intendedto limit the present disclosure. The term “surgical field” refers to thespace in which the surgical procedure is performed, and the term“surgical cavity” refers to a cavity at least partially surrounded bytissue.

Referring now to FIG. 1, a retractor system 10 is illustrated. Theretractor system 10 includes a retractor 100, a first retractor blade200 a, a second retractor blade 200 b, the first and second retractorblades 200 a, 200 b coupled to and extending distally from the retractor100 forming an opening in tissue of a patient. The retractor 100 has anauxiliary blade 300 coupled thereon, the auxiliary blade 300 extendingdistally from the retractor 100. Retractor blades 200 a, 200 b may beoriented in a caudal-cephalad orientation with auxiliary bladepositioned in a medial or lateral orientation. The retractor blades 200a, 200 b have an interbody spacer insertion instrument 80 disposedbetween them with a spacer 500 coupled at a distal portion of theinsertion instrument 80.

Referring now to FIGS. 1A-1C, the retractor 100 is illustrated. Theretractor 100 allows access to a target disc or target discs positionedbetween vertebrae “V” (FIG. 1), such as thoracic or lumbar vertebrae,and is referred to generally as retractor 100. The retractor 100includes a first support 110 having arms 130, 132 extending from thefirst support 110. A second support 120 is configured to slidablyreceive and engage the arms 130, 132, enabling the second support 120 tooperably couple to the first support 110 at a plurality of locationsalong the arms 130, 132. The first and second supports, 110, 120 areconfigured to receive and support retractor blades 200 a, 200 b (FIG.2B) that, when assembled, extend distally from the respective supports110, 120. In use, longitudinal movement of the second support 120relative to the first support 110 along the arms 130, 132 allowslongitudinal movement of the retractor blades 200 a, 200 b along an axisA-A. The retractor blades 200 a, 200 b are removably secured to thefirst and second supports 110, 120, though it is contemplated that, inembodiments, the retractor blades 200 a, 200 b may be permanentlycoupled to the first and second supports.

The arms 130, 132 of the retractor 100 define cavities 133, 134 thatextend along an axis A-A at least partially along a length of the arms130 132. The cavity 133 of the arm 130 includes teeth 136 that extendalong an upper side of the arm 130, the teeth 136 are configured tooperatively engage a translation knob 122 of the second support 120. Inembodiments, it is contemplated that any portion of the surfaces definedby cavities 133, 134 may have teeth or other grooves disposed thereonthat may be engaged by one or more translation knobs associated witheach arm 130, 132, as desired. The translation knob 122 is configured tosecure the second support 120 at a particular location on the arm 130when the translation knob 122 is rotatably engaged. Additionally, thecavities 133, 134 are configured to accommodate locking wheels 135, 137that are translatably disposed in respective cavities 133, 134. Eachlocking wheel 135, 137 is configured to secure an auxiliary blade 300(FIG. 2C) at a position along the respective arm 130, 132.

With additional reference to FIG. 1, as noted above, the retractorblades 200 a, 200 b preferably are releasably attached to the firstsupport 110 and the second support 120. An engaging arm 202 (FIGS. 2A,2B) of each retractor blade 200 a, 200 b engages an underside of thefirst or second support 110, 120. The first and second supports 110, 120define cavities 119, 129, that are configured to detachably secure theprotruding portions 204 of the retractor blades 200 a, 200 b (FIGS. 2A,2B) therein. Both the first and second supports 110, 120 include lockingsliders 118, 128 that slidably engage the protruding portion 204 of theretractor blades 200 a, 200 b to releasably secure the protrudingportions 204 of the retractor blades 200 a, 200 b within the cavities119, 129. The locking sliders 118, 128 are operatively coupled torespective biasing members 115, 125 (FIG. 1C) such that the lockingsliders 118, 128 are biased toward a locked state. Engaging portions121, 127 (FIG. 1C) of the locking sliders 118, 128 engage grooves 206(FIG. 2A, 2B) defined in protruding portions 204, thereby releasablysecuring the retractor blades 200 a, 200 b to the first support 110 andthe second support 120. The first support 110 further defines a pair ofrecessed portions 112, 114 aligned with cavities 133, 134 and configuredto accommodate respective locking wheels 135, 137 therein. The lockingwheels 135, 137 allow approximation of the first and second supports110, 120 to a closed cooperative position, with the locking wheels 135,137 nested in the recessed portions 112, 114.

As noted above, the second support 120 includes a translation knob 122that is rotatably mounted on, and configured to move, the second support120 to a particular position along the arms 130, 132. A ratchet (notexplicitly shown) engages the teeth 136 of the arm 130 as the first andsecond supports 110, 120 move away from one another. Similarly, whenmoving the second support 120 toward the first support 110, thetranslation knob 122 is rotated in the opposite direction when theratchet is released. The second support 120 includes a ratchet assemblyconfigured to allow uni-directional movement of the second support 120and lock the second support in position along the arms 130, 132. Theratchet assembly includes a ratchet knob 124 configured to releaseand/or disengage the ratchet assembly with arm 130 to allow selectiveuni-directional movement of the second support 120.

Referring now to FIGS. 2A and 2B, retractor blades 200 a, 200 b areconfigured to releasably couple to the first support 110 and the secondsupport 120, respectively. Each retractor blade 200 a, 200 b has anengaging arm 202 and a blade portion 208 extending therefrom. Theengaging arm 202 is configured to engage the underside of either thefirst or the second support 110, 120. The blade portion 208 is insubstantially orthogonal relation to the engaging arm 202. By virtue ofthe relation of the blade portion 208 to the engaging arm 202, the bladeportion 208 extends substantially orthogonally from the first or secondsupport 110, 120 when assembled. It is contemplated that, inembodiments, the blade portion 208 may be coupled to the engaging arm202 at varying angles such that the blade portion 208 may form apredetermined fixed angle with the engaging arm 202, and by extension,the first or second support 110, 120.

The engaging arm 202 includes a protruding portion 204 configured toextend through one of the cavities 119, 129 of the first or secondsupport 110, 120, respectively. Specifically, each protruding portion204 defines a groove 206 configured to securely engage the respectiveengaging portions 121, 127 (FIG. 1C) of the locking sliders 118, 128.

One or more longitudinal guide channels 209 extend substantially alongthe blade portion 208 distally from the engaging arm 202. Thelongitudinal guide channels 209 may extend along the entire length ofthe blade portion 208, though in embodiments the longitudinal guidechannels 209 may extend distally a part of the way along the bladeportion 208. In use, when the retractor blades 200 a, 200 b of therespective first and second supports 110, 120 are in close cooperativealignment, the opposing longitudinal guide channels 209 of the opposingblade portions 208 define one or more lumens configured to receive, forexample, a guide wire, a guide pin, or other surgical implementstherethrough (not shown). The longitudinal guide channels 209 may berounded or may be shaped so as to form a semi-elliptical cross sectionto hold a pin in place therein (via e.g., a friction fit); the pin beingremovable when sufficient proximal force is applied. The distal portionof the blade portion 208 may form a concave profile adapted to engageand accommodate the contour of a vertebral body. In some embodiments,the concave recess defines a radius of curvature from about 0.1 inchesto about 1.0 inches, and more preferably 0.6 inches. It is contemplatedthat, in embodiments, the clinician may select a retractor blade 200 aor 200 b having any particular radius of curvature as desired toaccommodate varying vertebral bodies that are engaged by the retractorblade 200 a or 200 b.

Referring now to FIG. 2C, an auxiliary blade 300 is shown that isconfigured to couple to one of the arms 130, 132 of the retractor 100 ina medial or lateral position. The auxiliary blade 300 includes anengaging arm 302 defining an orifice 303 of varying dimensions and ablade portion 308 extending from the engaging arm 302. The orifice 303of the engaging arm 302 is configured to be secured along the length ofthe arms 130, 132. More particularly, the orifice 303 defines anenlarged portion 304 and a narrowed portion 306 (e.g., a keyholeconfiguration). The enlarged portion 304 of the orifice 303 isconfigured to receive therethrough locking wheel 135, 137 of the firstor second arm 130, 132, respectively, such that the engaging arm 302 ofthe auxiliary blade 300 may be positioned on one of the arms 130, 132 ina superimposed relation and secured by the respective locking wheel 135,137. A neck portion 139 (FIG. 1B, 1C) of the locking wheel 135 isconfigured to be slidably received in the narrowed portion 306 of theauxiliary blade 300. A neck portion (not shown) of locking wheel 137 issimilarly configured to be slidably received in the narrow portion 306of the auxiliary blade 300. The blade portion 308 is substantiallyorthogonal with respect to the engaging arm 302, whereby when theauxiliary blade 300 is secured to one of the arms 130, 132, the bladeportion 308 is substantially orthogonal to the respective arm 130, 132.Additionally, each blade portion 308 includes at least one longitudinalguide channel 309 extending substantially along the length of the bladeportion 308, similar to the longitudinal guide channels 209 of theretractor blade 200. Likewise, similar to retractor blades 200 a, 200 b,the longitudinal guide channels 309 of the auxiliary blade 300 areconfigured to receive a guide wire, a guide pin, or other surgicalimplements therethrough.

In embodiments, and with additional reference to FIG. 6B, thelongitudinal guide channels 209, 309 of retractor blades 200 a, 200 band/or auxiliary blade 300 are shaped to correspond to a shape of achannel guide 721 c. The retractor blades 200 a, 200 b or auxiliaryblade 300 may be configured to enable longitudinal translation of theinsertion guides 721 through at least a portion of the longitudinalguide channel 209, 309 therealong. For example, the insertion guide 721,that is configured to couple to the insertion system 700, includes achannel guide 721 c that further includes a neck portion and a roundedhead portion. The neck portion and rounded head portion may beconfigured for slidable reception by the longitudinal guide channels209, 309, each having a corresponding pattern formed along the surfaceof the longitudinal guide channels 209, 309. It will be understood thatin such embodiments, the shape of the insertion guide 721 andcorresponding longitudinal guide channels 209, 309 are keyed to controlmotion of the insertion system 700 and the implant associated with theinsertion system so as to prevent unintended movement or “walking” ofimplants, plates, or combinations thereof during insertion between thevertebrae of patients. It will be further understood that the retractorblade 200 and/or the auxiliary blade 300 may be oriented in the cephaladdirection (e.g., a cephalad blade), the caudal direction (e.g., a caudalblade), the posterior direction (e.g., a posterior blade) and theanterior direction (e.g., an anterior blade) to enable translation ofinsertion guides 721 along the respective portions of the patient asdesired by the clinician, further allowing for increased flexibility. Itis contemplated that the insertion guide 721 may be provided in avariety of sizes that allow the spacing between the auxiliary blade 300(or blade 200) and the outer tubular member 712 of the insertion system700 (FIG. 6A) to vary allowing increased flexibility in placement of thespacer 500 between adjacent vertebrae. Insertion guides 721 having avariety of sizes may be provided in a kit.

The auxiliary blade 300 may be adjustably secured to the arms 130, 132.Specifically, the neck portion 139 of the locking wheels 135, 137 may beslidably received through the narrowed portions 306 of the cavities 303of corresponding auxiliary blades 300 to allow the clinician to positionthe auxiliary blades 300 in the transverse direction, as well as thelongitudinal direction along the axis A-A along the arms 130, 132. Oncepositioned along one of the arms 130, 132 the clinician may rotate oneof the locking wheels 135, 137 in a first direction to secure theauxiliary blade 300 to one of the arms 130, 132. To remove or repositionthe auxiliary blade 300, the clinician may rotate one of the lockingwheels 135, 137 in a second direction opposite the first direction,thereby partially or completely releasing the auxiliary blade 300 fromone of the arms 130, 132.

Referring now to FIGS. 2D and 2E, an alternate embodiment of theauxiliary blade 300 of FIG. 2C is illustrated and referred to as curvedblade 300′. The curved blade 300′ is substantially similar to theauxiliary blade 300. The curved blade 300′ includes a hand-grippableportion 312, a planar surface 307 extending distally from thehand-grippable portion 312, and an arcuate portion 310 extendingdistally from a distal portion of the planar surface 307. The planarsurface 307 and the arcuate portion 310 are configured to slidablyreceive a shuttle 301. More particularly, the shuttle 301 includes achannel which receives the planar surface 307 and/or arcuate portion 310therethrough. A shuttle pin 314 extends through the shuttle 301, androtatably engages a bore (not explicitly shown) defining a threadedsurface. Longitudinal guide channel 309 does not extend to the distalend of the auxiliary blade 300′ as seen in FIG. 2D. This provides alimit stop such that an instrument traveling along the longitudinalguide channel 309 stops prior to reaching the distal end of theauxiliary blade 300′. In situations where a cutter (e.g., knife,scalpel, or other cutting instrument) is used to cut tissue (e.g., theALL), the distal end of the longitudinal guide channel 309 limits howfar the cutter travels along the auxiliary blade 300′ into the workingspace such that the cutter is inhibited from cutting too far and riskingdamage to surrounding tissue and vasculature.

The planar surface 307 and the arcuate portion 310 have a longitudinalguide channel 309 extending along at least a portion of both the planarsurface 307 and the arcuate portion 310. The arcuate portion 310 isdefined in part by a predetermined radius of curvature. In use, when thecurved blade 300′ is introduced to a working channel of a patient toretract tissue, by virtue of the curvature of the arcuate portion 310the tissue engaged by the arcuate portion 310 is retracted less than thetissue retracted by the planar surface 307. This may allow the clinicianto retract the tissue located proximally farther than the tissue locateddistal to the clinician (when looking toward the vertebra of thepatient), thereby reducing the chance for trauma to the distal tissue.The arcuate portion 310 of the curved blade 300′ may also be shaped ortoed inward such that, the arcuate portion 310 approximates the shape ofthe anterior portion of the vertebra when advanced toward the vertebraduring surgical procedures. In embodiments, during surgical procedures,the distal portion of the curved blade 300′ may be advanced such thatthe arcuate portion 310 extends along a side portion of the vertebra ofthe patient. The curved blade 300′ further includes a cylindrical member311 that rotatably couples the planar surface 307 to the engaging arm302 within an engagement channel 313. The hand-grippable portion 312 ofthe curved blade 300′ further includes a plurality of grooves or otherergonomic features disposed thereon to facilitate grip of the curvedblade 300′ by the clinician during surgical procedures.

To fix the shuttle 301 and the engaging arm 302 relative to the planarsurface 307 or arcuate portion 310, the shuttle pin 314 is advancedinward until the shuttle pin 314 mechanically engages a side portion ofeither the planar surface 307 or arcuate portion 310. As such, theshuttle pin 314 enables selective positioning of the engaging arm 302along the planar surface 307 or arcuate portion 310. When the shuttlepin 314 is retracted, it disengages from either the planar surface 307or the arcuate portion 310, which allows the curved blade 300′ to moveup and down along the planar surface 307 and/or the arcuate portion 310with respect to the engaging arm 302, thereby allowing the clinician toset the height at which the curved blade 300′ is positioned with respectto the engaging arm 302. A toe screw 316 extends through an arm 315extending from the shuttle 301. The toe screw 316 is configured torotatably engage the engaging arm 302 to allow the engaging arm 302 totoe inwards or outwards relative to the planar surface 307. Inembodiments, accessories may also be coupled to a shuttle (not shown)such as, without limitation, a light to the auxiliary blade 300 orcurved blade 300′. In embodiments, the accessories may also be attachedto the retractor blade 200.

Referring now to FIGS. 3A and 3B, a dissector 400 is illustrated for usewith the retractor 100. While shown at a certain scale and as extendinga predetermined marked distance, it will be understood that thedissector 400 may be formed to have a wider or narrower cross-section,and may be longer or shorter, depending on the particular needs of aclinician during a surgical procedure. The dissector 400 has a centralpassage 402 extending along the length of the dissector 400 with openproximal and distal portions. The central passage 402 is configured suchthat the dissector 400 may slidably receive a guide wire or guide pintherethrough (not shown). The guide wire or guide pin may guide thedissector 400 to the target disc of a patient during a surgicalprocedure. Additionally, the dissector 400 may have indicia marked(e.g., etched, printed or printed thereon) to indicate the depth of thebody cavity or the distance between the epidermal tissue surface and thevertebral body. The clinician may use such indicia to select anappropriate retractor blade during the surgical procedure. Inembodiments, the central passage 402 is defined by an electricallyconductive tube with plastic over molded onto and surrounding the tube.A notch 404 is formed along the proximal portion of the dissector 400 inassociation with an electromyography system in a known manner. A clipfrom the electromyography system can be contacted with the conductivetube at the notch 404 with the signals transmitted along the tube insidethe insulating plastic outer body, to the distal portion and/or distaltip of the conductive tube that contacts tissue.

Referring now to FIGS. 4A-4C, a spinal interbody spacer or spacer 500for placement between vertebrae is illustrated. The spacer 500 includesa pair of opposing side walls 510, 504, a blunt nose 506, and an arcuateproximal wall 502. The spacer 500 may be monolithically formed and maybe made of any suitable biocompatible material such as, withoutlimitation, polyetheretherketone (“PEEK”), polyphenylsulfonee (e.g.,Radel®), polyetherimide (e.g., Ultem®), stainless steel, cobalt chrome,titanium, titanium alloys, and the like.

The spacer 500 defines a generally torpedo-shaped profile with anopening “C” extending therethrough to enable bone growth betweenadjacent vertebrae. Additionally, opening “C” is configured toaccommodate additional bone graft material. The blunt nose 506 includesa substantially contoured, tapered surface to facilitate insertionthereof between the vertebral bodies. The spacer 500 includes avertebral body engaging top and bottom surfaces 512, 514 havingprotrusions configured to facilitate gripping and securing of the spacer500 with adjacent vertebrae. In particular, the protrusions includering-patterned protrusions 508 concentrically arranged with respect tothe opening “C”. Additionally, the ring-patterned protrusions 508 of theopposing top and bottom surfaces 512, 514 may be configured to allowsecure engagement with respect to each other when disposed in superposedrelation. In embodiments discussed below, the interbody spacer may haveopposing surfaces configured to expand upon mechanical engagement by aninterbody spacer insertion system or insertion system 700 (FIGS. 6A, 6B)so as to enable the clinician to adjust the lordotic curvature of thepatient once the interbody spacer is positioned between the vertebrae ofthe patient.

With continued reference to FIG. 4C, an arcuate proximal wall 502includes a recess 518 defining a threaded aperture 516 for mating withan insertion system 700 (FIGS. 6A, 6B). The top and bottom surfaces 512,514 of the spacer 500 are substantially parallel to one another. Inembodiments, the top and bottom surfaces may be in angled relation. Thespacer 500 may be tapered laterally and define a generally wedge shapedconfiguration. Specifically, one sidewall may have a height that isdifferent from the height of the opposing sidewall defining the taperedor lordotic or hyperlordotic configuration. Alternatively, the opposingside walls may have the same height, and thus defining a parallelconfiguration.

For a detailed description of interbody spacers, including expandableinterbody spacers, reference may be made to commonly owned U.S. PatentApplication Publication No. 2017/0135824 entitled “Expandable SpinalImplant” and U.S. Pat. No. 9,468,535 entitled “Interbody Spacer” thecontents of which are hereby incorporated by reference in theirentirety.

Referring now to FIG. 4D, an interbody spacer attachment plate orattachment plate 520 configured to couple to the spacer 500 (FIGS.4A-4C) when fixing the spacer 500 to corresponding vertebrae isillustrated. The attachment plate 520 defines a pair of opposed surfaces522 which extend along an axis B-B. A pair of screw bores 524 extendsthrough the attachment plate 520 between openings in the opposedsurfaces 522. The screw bores 524 are configured to receive bone screws(not shown) therein. The screw bores 524 are substantially circular.Each screw bore 524 has a center point and radius extending outward fromthe center point to an edge of the screw bore 524. An attachment bore526 is interposed between the screw bores 524 and extends through theattachment plate 520. The attachment bore 526 has a center which ispositioned along the B-B axis, and a radius extending from the center toa threaded surface configured to engage an attachment screw (not shown).In embodiments, the screw bores 524 and/or the attachment bore 526 maybe tapered such that the radius of the bore decreases between pair ofopposed surfaces 522 in a proximal to distal direction.

The respective centers of the screw bores 524 are offset relative to thecenter of the attachment bore 526 such that an angle Θ is formedrelative to the axis B-B. In particular, the screw bores 524 are offsetin an anterior-posterior orientation such that the centers of the screwbores 524 define the angle Θ with respect to the center of theattachment bore 526, which lies along the axis B-B. The angle Θ may beanywhere from about 5 degrees to about 30 degrees, though inembodiments, it is contemplated that the angle may be any suitable anglebetween about 5 degrees and about 20 degrees. It will be appreciatedthat the angle Θ need not be identical for each of the screw bores, andthat one screw bore may be offset from axis B-B by a greater angle thanthe other screw bore. By virtue of the offset of the screw bores 524relative to the attachment bore 526, the position of screw bores 524 isoriented in a direction so that anatomical structures (e.g., nerves,tissue and blood vessels) located on the side of the plate opposite toaxis B-B from screw bores 524 are avoided, and the potential for damageto such structures as screws are inserted through the screw bores isminimized or reduced. In general, the screw bores are oriented in aposterior direction to avoid anteriorly oriented structures.Additionally, by virtue of the offset of the attachment bore 526 andpair of screw bores 524, the attachment plate 520 may be coupled to animplant (e.g., spacer 500 shown in FIGS. 4A-4C) while being positioned.Such positioning of the attachment plate 520 relative to the vertebraeof the patient provides the additional benefit of allowing the plate 520to, when positioned in certain locations (e.g., along vertebraeassociated with the lumbar part of the vertebral column) more closelyapproximate or match the curvature or lordosis of the associatedvertebrae. For additional detail including an example of a suitable bonescrew, reference may be made to commonly-owned U.S. Pat. No. 8,137,405,the contents of which are hereby incorporated by reference in theirentirety.

Referring now to FIGS. 5A-5G, an expandable interbody spacer 600 isshown. The expandable interbody spacer 600 includes a first body portion602 and a second body portion 604 configured to rotatably couple to thefirst body portion 602. The first and second body portions 602, 604 arerotatably coupled via a rod 606 so that the first body portion 602 andsecond body portion 604 pivot relative to one another about an axis B-Bdefined by the rod 606. The first body portion 602 and the second bodyportion 604 have a corresponding first bone screw mount 610 and a secondbone screw mount 612 disposed at a proximal end of the first and secondbody portions 602, 604, respectively. In embodiments, the first andsecond bone screw mounts 610, 612 may be offset from a central portionof the expandable interbody spacer 600 when viewed from the proximalportion (e.g., the first and second bone screw mounts 610, 612 may beoffset in the anterior or posterior directions) depending on the desiredfinal position of the expandable interbody spacer 600. In embodimentswhere the first and second bone screw mounts 610, 612 are offset fromthe central portion of the expandable interbody spacer 600, such offsetmay be to increase the distance between the first and second bone screwmounts 610, 612 and tissue, nerves, or other anatomic features of theindividual in the opposite direction. In particular, the first andsecond bone screw mounts 610, 612 may be disposed in a posteriordirection as discussed in connection with the screw bores 524 ofattachment plate 520 so that the screws are spaced from vessels andnerves disposed more anteriorly. A pawl beam 614 is rotatably coupled tothe second body portion 604 and configured to engage an engagement wall616 extending from the first body portion 602. For purposes of clarity,reference will be made to a left portion and a right portion of theexpandable interbody spacer 600, and components associated therewith.The left portion is to be understood as referring to the portion of theexpandable interbody spacer 600 configured to rotatably pivot duringexpansion of the expandable interbody spacer 600. The right portion ofthe expandable interbody spacer 600 is to be understood as referring tothe portion of the expandable interbody spacer 600 configured to fix theorientation of the first body portion 602 relative to the second bodyportion 604 when the expandable interbody spacer 600 is expanded.

The first body portion 602 has an upper surface 620 having a pluralityof protrusions 620 a extending upward therefrom and a plurality ofmicro-apertures 620 b. The protrusions 620 a are configured to inhibitexpulsion and/or movement of the expandable interbody spacer 600 byengaging an endplate of the vertebra adjacent the upper surface when theexpandable interbody spacer 600 is positioned between adjacentvertebrae. The micro-apertures 620 b extend from the upper surface 620through the first body portion 602 downward to a lower surface (notexplicitly shown) of the first body portion 602, and are configured toenable bone growth therethrough during spinal fusion of the vertebrae ofthe patient. The first body portion 602 further defines an opening 622located centrally along the upper surface 620, the opening 622 extendingdownward from the upper surface 620 toward the second body portion 604.While the first body portion 602 and the opening 622 are shown forming asubstantially elliptical shape, it will be understood that the aperturemay take any variety of shapes (e.g., a circle, square, and the like).The opening 622 allows bone growth between adjacent vertebrae and alsoprovides an area for packing the expandable interbody spacer 600 withbone growth material.

The first body portion 602 has the first bone screw mount 610 disposedalong a proximal portion of the first body portion 602, the first bonescrew mount 610 extending proximally and upward relative to the uppersurface 620 of the first body portion 602. The first bone screw mount610 defines an aperture 610 a configured to receive a first bone screwwasher 610 b therein. The first bone screw washer 610 b is made of arelative soft material (e.g., commercially pure titanium) configured todeform as a bone screw (not explicitly shown), formed of a hardermaterial (e.g., titanium alloy Ti-6Al-4V), is inserted and engages thefirst bone screw washer 610 b. The aperture 610 a is angled so as todirect a screw inserted therethrough into the adjacent vertebral body.

The first body portion 602 has a rotation cylinder 624 extendingdownward along a left portion of the first body portion 602. Therotation cylinder 624 is configured to receive the rod 606 therein toenable rotation about an axis B-B (FIG. 5A). More particularly, therotation cylinder 624 is configured to mate with a curved indent 626 inthe second body portion 604. The micro-apertures 620 b which are alignedwith the rotation cylinder 624 extend therethrough.

The first plate 602 has an engagement wall 616 extending downward fromthe right portion of the first body portion 602. The engagement wall 616has teeth 616 a extending distally from a proximal portion of theengagement wall 616. The teeth 616 a further extend from the engagementwall 616 inward toward the aperture of the first and second bodyportions 602, 604. The teeth 616 a of the engagement wall 616 areconfigured to engage teeth 614 a of the pawl beam 614 to maintain theposition of the first body portion 602 relative to the second bodyportion 604 when the expandable interbody spacer 600 is in an openconfiguration (FIG. 5G).

The second body portion 604 has an upper surface 628 including aplurality of micro-apertures 630 extending from the upper surface 620 ofthe second body portion 604 to a lower surface (not explicitly shown) ofthe second body portion 604. The second body portion 604 has a pluralityof protrusions 632 extending downward from a lower surface (notexplicitly shown) of the second body portion 604. Similar to theprotrusions 620 a of the first body portion 602, the protrusions 632 ofthe second body portion 604 are configured to inhibit expulsion andmovement by the expandable interbody spacer 600 relative to thevertebrae of the patient by engaging an endplate of an adjacentvertebra.

In embodiments, the micro-apertures 620 b of the first body portion 602vertically align with the micro-apertures 630 of the second body portion604 when in the closed configuration (FIG. 5B). The second body portion604 has a proximal region 634 and a distal region 636 which extend fromthe upper surface 628 of the second body portion 604. The proximal anddistal regions 634, 636 are configured to support the first body portion602 when the expandable interbody spacer 600 is in the closedconfiguration (FIG. 5B), the first body portion 602 vertically offsetfrom the second body portion 604.

The second body portion 604 has a curved indent or recess 638 whichforms a surface disposed along the left portion of the second bodyportion 604 which, as noted above, is configured to mate with therotation cylinder 624 of the first body portion 602. A pair of apertures640 extends proximally and distally from the surface formed by therecess 638 to form corresponding bores through at least a portion of theproximal and distal regions 634, 636, respectively. The recess 638 isconfigured to rotatably receive the rotation cylinder 624 therein. Theaperture 640 extending distal from the recess 638 extends to the distalportion of the second body portion 604, enabling insertion of therotation cylinder 624 from the distal portion of the expandableinterbody spacer 600. The apertures 640 are configured to receive therod 606 for pivotally coupling the first body portion 602 and the secondbody portion 604.

Similarly, a pair of apertures 642 is disposed on opposing sides of acavity formed by the proximal and distal regions 634, 636 along theright portion of the second body portion 604. The apertures 642 are incoaxial alignment and form corresponding bores which extend proximallyand distally from the cavity through at least a portion of the proximaland distal regions 634, 636. The bore extending from the aperture of thedistal region 636 extends to the distal portion of the distal region 636and is configured to receive a pawl rod 608 therein.

The first body portion 602 has an aperture 644 disposed on the proximalportion of the first body portion. The aperture 644 defines acorresponding bore which extends distally through the first body portion602. The bore has a threaded surface that is configured to receive afixation screw (not shown) configured to couple the expandable interbodyspacer 600 to an insertion tool (e.g., the insertion system 700 (FIG.6A)).

The pawl rod 608 is configured to rotatably support the pawl beam 614 inthe cavity formed between the proximal and distal regions 634, 636 ofthe second body portion 604. The pawl beam 614 includes a rotation beam614 b and an engagement beam 614 c coupled to an upper surface of therotation beam 614 b. The rotation beam 614 b has a pair of apertures 614d in coaxial alignment, the apertures 614 d defining a bore extendingthrough the rotation beam 614 b. The bore extending through the rotationbeam 614 b is configured to receive the pawl rod 608 therein and enablesrotatable engagement of the pawl beam 614 and the teeth 616 a of theengagement wall 616. More particularly, the engagement beam 614 cincludes teeth 614 a configured to engage the teeth 616 a of theengagement wall 616 (FIGS. 5D and 5G) to maintain the orientation of thefirst body portion 602 relative to the second body portion 604 when inan expanded configuration (FIG. 5E). Coil springs 646 are configured tobe positioned about proximal and distal portions of the pawl rod 608.The coil springs 646 are configured to apply rotational force to theengagement beam 614 c to bias the pawl rod 608 outward toward theengagement wall 616 of the first body portion 602 to urge the teeth 614a into engagement with teeth 616 a. The pawl rod 608 has a slot formedalong the proximal end of the pawl rod 608 which is accessible through abore defined by an aperture 648, the bore extending through the proximalregion 634 of the second body portion 604.

The expandable interbody spacer 600 may be inserted between thevertebrae of a patient in conjunction with the retractor system 10 ofFIG. 1 and/or in a manner similar to the method described with respectto FIG. 9. It is contemplated, however, that the expandable interbodyspacer 600 may be inserted between the vertebrae by any other suitablemethod known in the art. In addition, the expandable interbody spacer600 may be inserted without engaging the retractor 100 as discussed.

Once positioned between the first and second vertebrae, a first bonescrew and a second bone screw, as are known in the art, are insertedthrough the first and second bone screw washers 610 b, 612 b that arepositioned in the apertures 610 a, 612 a and into the adjacent vertebraethereby rotatably coupling the expandable interbody spacer 600 to thefirst and second vertebrae of the patient. The first and second bonescrews may be driven through pre-drilled holes established in thevertebrae of the patient. Alternatively, the first and second bonescrews may be self-starting bone screws which do not requirepre-drilling vertebrae before fixation thereto. As the first and secondbone screws are inserted into the vertebrae, the first and second bonescrews deform the corresponding bone screw washers 610 b, 612 b, fixingthe first and second body portions 602, 604 to the respective vertebrae.Other structures known in the art, such as set screws, cover plates orwashers, etc. are also contemplated for securing the screw to theimplant.

With continued reference to FIGS. 5A-5G, and additional reference toFIGS. 8A-8D, engagement of the expandable interbody spacer 600 will bediscussed in detail. Once inserted between the vertebrae of the patientand attached thereto, the first body portion 602 may be rotated relativeto the second body portion 604 about the rod 606. To rotate the firstbody portion 602 relative to the second body portion 604, the blade 808of the expander 800 (FIG. 8A) is inserted between the first and secondbody portions 602, 604. The expander 800 is rotatably engaged by aclinician to cause the edge 808 b of the blade 808 to pivot about therounded portion 808 a in a first direction, causing the edge 808 b tocome into contact with the first body portion 602 of the expandableinterbody spacer 600. As the expander 800 is rotated further, the firstbody portion 602 is rotated upward, causing the teeth 614 a of the pawlbeam 614 to ratchet and engage the teeth 616 a of the engagement wall616 of the first body portion 602. The ratcheting of the first bodyportion 602 relative to the second body portion 604 enables theclinician to transition the expandable interbody spacer 600 from aclosed configuration (FIG. 5C) to an open configuration (FIG. 5E). Oncein the open configuration, and more particularly when a desired amountof lordosis is established between first and second vertebrae of thepatient, the expander 800 is rotated in a second direction differentfrom the first direction, thereby causing the blade 808 of the expander800 to disengage from the expandable interbody spacer 600. The teeth 616a of the engagement wall 616 rest on the teeth 614 a of the pawl beam614, thereby maintaining the position of the first body portion 602relative to the second body portion 604 during spinal fusion of thevertebrae of the patient. This arrangement between the teeth 614 a andthe teeth 616 a inhibits collapse of the expandable interbody spacer600. Alternative modes of expanding the expandable interbody spacer alsoare contemplated. In the simplest aspect, the expandable interbodyspacer may be permitted to passively expand as the patient isrepositioned, with the expandable interbody spacer settling into anatural or desired position of lordosis based on patient positioning. Inthe alternative, the first and second body portions 602, 604 may bemoved apart by expansion mechanisms such as a mechanical scissor jack,hydraulic expander or other known mechanisms.

It will be understood that, in embodiments, the coil springs 646 may beconfigured to apply an outward force such that when the expandableinterbody spacer 600 is in a collapsed configuration, when released, theexpandable interbody spacer 600 transitions to an open configuration(see FIG. 5E). More particularly, during a surgical procedure theexpandable interbody spacer 600 may be locked or otherwise held in aclosed configuration by the insertion system 700 prior to positioningbetween vertebrae of a patient. Once positioned as desired betweenvertebrae of a patient, the clinician positioning the expandableinterbody spacer 600 may cause the insertion system 700 to release theexpandable interbody spacer 600. Upon release, the first and second bodyportions 602, 604 may be urged to pivot about the rod 606 toward theopen configuration, without being urged apart by the clinician. Byallowing the expandable interbody spacer 600 to expand without theapplication of force by a clinician, an angle of lordosis maybe achievedwithout over or under expanding the expandable interbody spacer 600 byapplying too much or too little rotational force.

Referring now to FIGS. 6A and 6B, illustrated is an interbody spacertranslation system or insertion system 700 for positioning a spacer 500between vertebrae of a patient during a surgical procedure. As will bedescribed later in detail, the insertion system 700 is coupled to aspacer 500 and guided along one of the retractor blades 200, 300, 300′.While the insertion system 700 is shown slidably engaging the auxiliaryblade 300, it will be apparent that the insertion system 700 may bepositioned to engage and translate along the longitudinal guide channels209 of the retractor blades 200 a, 200 b.

The insertion system 700 includes a housing 704 defining a bore that isconfigured to slidably receive an inner tubular member 708 therethrough.When assembled, a handle 702 of the housing 704 is in orthogonalrelation with the inner tubular member 708 extending distally therefrom.The housing 704 includes a proximal portion configured to receive arelease assembly 706 that releasably couples to the inner tubular member708.

The inner tubular member 708 extends distally from the housing 704through a bore defined by an outer tubular member 712. The outer tubularmember 712 has a hand-grippable portion 710 with a bore extendingtherethrough coupled proximally to the outer tubular member 712. Inembodiments, the hand-grippable portion 710 includes a plurality of ribs710 a, or other ergonomic features that enhance gripping thehand-grippable portion 710, extending outward about the hand-grippableportion 710 to allow the clinician to grip and rotate the hand-grippableportion 710. The outer tubular member 712 may have one or more windows714 disposed along the outer tubular member 712 and extendingtherethrough to allow visual inspection of the inner tubular member 708when inserted through the outer tubular member 712. More particularly,the windows 714 may allow visual inspection of indicia or instrumentfeatures of instruments disposed within the bore of the outer tubularmember 712 such as, for example, the inner tubular member 708. Thewindows 714 also may facilitate cleaning and sterilization of theinstrument between uses.

The distal portion of the inner tubular member 708 has a coupling 716disposed at the end thereof. The coupling 716 is configured to berotatably engaged by either the hand-grippable portion 710 or therelease assembly 706. More particularly, counter-clockwise rotation ofthe hand-grippable portion 710 causes the outer tubular member 712 torotatably engage the coupling 716, causing arms 718 a, 718 b to moveaway from one another. Conversely, clockwise rotation of thehand-grippable portion 710 when the arms 718 a, 718 b are in an expandedconfiguration causes the arms 718 a, 718 b to move toward one another.Such movement of the arms 718 a, 718 b towards and away and from oneanother allows the arms 718 a, 718 b to engage the attachment plate 520(FIG. 4D) or the expandable interbody spacer 600 (FIG. 5A).

With particular reference to FIG. 6B, the distal portion of theinsertion system 700 is shown, with parts separated. The coupling 716has two arms 718 a, 718 b in opposed relation. The arms 718 a, 718 b arebiased inwards relative to the inner tubular member 708 and couple to aninternal actuation assembly (not shown) that by default maintains thearms 718 a, 718 b in a close cooperative position relative to oneanother. When the release assembly 706 is engaged, the arms 718 a, 718 bare moved away from each other. This outward motion expands the distancebetween a first hook 720 a and a second hook 720 b. A screw engagementmechanism (not shown) has an engagement portion that is configured to bereceived in an opening of a screw 722. The screw engagement mechanismmay be a tubular member that extends through a bore defined by the innertubular member 708 and may rotate either independent of the innertubular member 708 or in concert with the inner tubular member 708. Inembodiments, the screw engagement mechanism may advance proximally ordistally to advance the screw 722 toward or away from the spacer 500.

The screw 722 includes a head with a recess configured to receive thescrew engagement mechanism therein, and a threaded portion extendingdistally from the head. The threaded portion is configured to extendthrough the attachment plate 520 (FIG. 4D). As discussed hereinabove,the plate 520 has a top surface defining the attachment bore 526extending through the attachment plate 520 distally toward the bottomsurface, an offset pair of screw bores 524 configured to receive bonescrews (not shown) therein, and a periphery extending distally from thetop surface to a bottom surface. The periphery has a pair of indents 528extending inward along the periphery of the attachment plate 520. Theindents 528 form an L shape indent configured to slidably receive thearms 718 a, 718 b when the arms are in an approximated configuration.The bottom surface has a pair of flanges 530 (FIG. 6B) extendingdistally from the attachment plate 520, the flanges 530 are configuredto slidably engage the recess 518 of the spacer 500. In embodiments, theflanges 530 may be configured to approximate the shape of the recess 518of the spacer 500.

Prior to insertion of the spacer 500 between vertebrae of a patient, thescrew 722 may be inserted and advanced distally through the attachmentplate 520. Once advanced through the attachment plate 520, the threadedportion of the screw 722 may rotatably engage the threaded aperture 516of the spacer 500 to secure the attachment plate 520 to the spacer 500.

To couple the coupling 716 to the attachment plate 520, thereby operablycoupling the insertion system 700 to the spacer 500, the actuationassembly (not shown) may be actuated by a clinician, thereby causing thearms 718 a, 718 b to expand outward. The arms 718 a, 718 b may beadvanced such that the first and second hooks 720 a, 720 b are alignedwith the opposing indents 528 of the attachment plate 520. Upon releaseof the actuation assembly, the arms 718 a, 718 b, and, by extension, thecorresponding first and second hooks 720 a, 720 b, advance inwards intothe indents 528, thereby securing the attachment plate 520 to theinsertion system 700. In the alternative, arms 718 a, 718 b may bebiased apart, with the actuation mechanism compressing the armstogether, such as with a compression tube, to grasp and hold theimplant. As will be appreciated, the inserter may be configured in thealternative to engage the expandable interbody spacer 600, as discussedherein.

With continued reference to FIG. 6B, an insertion guide 721 may becoupled to the insertion system 700 to guide the insertion system 700along the longitudinal guide channel 209 defined by the retractor blade200 a, 200 b or the longitudinal guide channel 309 defined by theauxiliary blade 300. The insertion guide 721 has a chassis 721 a havingan arcuate surface 721 b and a channel guide 721 c. The arcuate surface721 b is configured to approximate an outer surface of either arm 718 a,718 b and/or the outer surface of the outer tubular member 712. Thechannel guide 721 c extends outward from the chassis 721 a and forms apair of concave surfaces that invert and form a convex head. The convexhead of the channel guide 721 c is configured to slidably engage thelongitudinal guide channel 309 defined by the auxiliary blade 300. Theinsertion guide 721 is coupled to the first or second arm 718 a, 718 bvia a screw 721 d. More particularly, the screw is configured to extendthrough a bore defined by the chassis 721 a of the insertion guide 721and a threaded aperture 719 a, 719 b of the corresponding arm 718 a, 718b. Alternatively, the insertion guide 721 may be integrally formed witha portion of the insertion device 700, or may be welded or otherwiseattached thereto by suitable means. In addition, other keyed shapes ofengagement between the insertion guide 721 and the retractor blades 200a, 200 b is contemplated, such as a dovetail joint.

The distal portion of the auxiliary blade 300 has a transverse boreextending at least partially therethrough, the transverse boreconfigured to receive a pin 309′ therein. The pin 309′ may be made oftantalum or any other substance known in the art that provides a clearindication of the position of the pin 309′, and by extension theposition of the auxiliary blade 300, in a fluoroscopic image capturedduring fluoroscopic imaging of the auxiliary blade 300.

Referring now to FIG. 7, illustrating the insertion system 700 engagingthe retractor system 10 of FIG. 1, discussed is a method described withreference to FIG. 9 that details an illustrative example of a method forreplacing a damaged intervertebral disc by the retractor system 10.While reference will be made to the insertion of the spacer 500 inconnection with the retractor 100, it will be understood that theexpandable interbody spacer 600 may be inserted in a similar manner. Itwill also be understood by one skilled in the art that the expandableinterbody spacer 600 may be inserted with an insertion system (e.g.,insertion system 700), without slidably engaging the longitudinal guidechannels 209 of the retractor blades 200 a, 200 b or the longitudinalguide channel 309 of the auxiliary blade 300 when guiding the expandableinterbody spacer 600 toward the vertebrae of a patient. In this regard,it will be understood that the insertion system 700 may be used duringsurgical procedures with retractors known in the art, or duringprocedures without the use of a retractor.

In use, a clinician positions a patient in a lateral decubitus positionwith the iliac crest of the patient located directly over a table break.The patient is then secured typically via straps or other knowntensioning devices, just below the iliac crest and over the thoracicregion of the patient. The legs are likewise secured to the table, so asto prevent movement of the patient during the surgical procedure. Oncesecured, fluoroscopic images of the patient are captured to obtainimages of the targeted disc or discs for replacement.

Referring now to FIG. 9, once the clinician is satisfied with theplacement of the patient and the obtained fluoroscopic images, anincision is made (block 902). In embodiments, when replacing one disc, atransverse incision is made, and when replacing multiple discs, avertical incision is made relative to the patient, to providesubcutaneous access to the iliac portion of the patient. Once thedesired incision is created, the exposed muscle fibers are separated bythe clinician as the clinician advances a finger into theretroperitoneal space of the patient. The peritoneum is releasedanteriorly as the retroperitoneal space is developed, allowing theclinician to gain access to the psoas muscle and/or the anterior tip ofthe transverse process. Once the clinician verifies development of theretroperitoneal space, a dissector is inserted, advanced through thepsoas muscle, and fixed directly to the middle of an intervertebral discor target disc. The clinician may move the dissector as desired to freesoft tissue surrounding the target disc, completing preparation of thepath to the spine of the patient (block 904).

Once the path is established at block 904, an intradiscal guidewire isplaced through the dissector and advanced into the disc of the patient.If additional dilation is desired by the clinician, the first dilatormay be removed, and a second dilator may be introduced in the place ofthe first dilator. The second dilator, larger than the first, is guidedto the target disc by following the path along the guidewire, keepingthe second dilator in line with the muscle fibers of the psoas andsafely anterior to the lumbar plexus. The clinician may move theproximal portion of the first and/or second dilator back and forth tofurther develop the surgical site (block 906). Once the dilator isseated in place as desired by the clinician, a measurement may be takenof the exterior tissue or skin of the patient relative to the first orsecond dilator so as to allow the clinician to select an appropriatepair of retractor blades (e.g., retractor blades that are at theappropriate length) (block 908). Once selected, the correspondingretractor blades are attached to the retractor 100. The retractor 100may be closed such that the retractor blades 200 a, 200 b are in closecooperative alignment. After removing the first or second dilator, theretractor 100 is inserted into the tissue and advanced toward the targetdisc and associated vertebrae. When the retractor is in position, theretractor 100 is rotated 90 degrees prior to expansion. Optionally, oneor more pins may be inserted through the longitudinal guide channels 209of the retractor blades 200 a, 200 b once rotated and fixed to thevertebrae of the patient (block 910). In an embodiment, a pin isinserted into the channel of one retractor and anchored in the bone ofone vertebra.

Once in place, and optionally secured, the retractor 100 is expanded(block 912). In the case where one pin is inserted into the groove ofone blade (e.g., the first retractor blade 200 a), expanding theretractor 100 causes the other blade (e.g., the second retractor blade200 b) to move away from the first retractor blade (200 a) which isfixed by the pin. Once the retractor 100 has been expanded, theguidewire may be removed, and the retractor 100 expanded further, asdesired by the clinician. As desired, where one or no pin has been used,additional fixation pins may be secured to the vertebrae as desired bythe clinician. If additional, transverse, retraction is desired, theauxiliary blades 300 may be inserted and coupled to the retractor 100.Once inserted, the auxiliary blades 300 may be expanded outward,retracting the corresponding tissue (block 914). An intradiscal shim(not shown) may be inserted as desired to prevent or reduce the chanceof soft tissue creep into a working channel of the surgical site duringthe surgical procedure (block 916). For additional support, atable-mounted surgical arm (not shown) may be attached to the retractor100 to maintain the position of the retractor assembly relative to thesurgical table, and by extension, the patient.

Once the working channel is established, a traditional annulotomy anddiscectomy are performed (block 918). The annulotomy and discectomy areperformed by first determining an appropriate interbody spacer, orsequence of spacers, to distract the space occupied by the target disc(block 920.) In embodiments, trial interbody spacers may be inserted andplaced in between the vertebrae (e.g., by advancing the trial interbodyspacer with a slap-hammer) to facilitate selection of a spacer 500 thatis appropriate.

When placing the spacer 500 selected by the clinician, the spacer 500 isthreadably coupled to the insertion system 700 via the attachment plate520 (block 922). This allows the clinician to insert the spacer 500 andattachment plate 520 into the intervertebral space as a single unit.Alternatively, the spacer 500 may be inserted into the intervertebralspace first and the attachment plate 520 is coupled to the spacer 500subsequent to placement in the intervertebral space. During placement, ahandle 702 may be used (or, where necessary, a slap-hammer (not shown)may be coupled) to the insertion system 700. The insertion system 700having the spacer 500 coupled distally thereto is advanced toward thevertebrae by aligning the insertion guide 721 with the longitudinalguide channels 209 (or longitudinal guide channels 309 when using theauxiliary blade 300). Once aligned, the channel guide 721 c is advanceddistally along the longitudinal guide channel 209 (or longitudinal guidechannel 309) (block 924). Once the spacer 500 is positioned as desiredby the clinician, the insertion system 700 may rotatably engage a screwengagement mechanism to remove the screw 722 from the threaded aperture516 of the spacer 500 (block 926), though removal may not be desired ornecessary, depending on the surgical procedure. The clinician placesbone screws through screw bores 524 in attachment plate 520 or, in thecase of expandable interbody spacer 600, through apertures 610 a, 612 a.It is contemplated that only one bone screw may be used with spacer 500.It is also contemplated that when using the expandable interbody spacer600, after the expandable interbody spacer 600 is positioned betweenadjacent vertebrae, one bone screw is inserted through one of theapertures 610 a, 612 a. Subsequent to inserting the bone screw throughone of the apertures 610 a, 612 a, the expandable interbody spacer 600is allowed to expand and a second bone screw is inserted in the other ofthe apertures 610 a, 612 a, thereby securing the expandable interbodyspacer 600 in position. Preferably, the bone screws are inserted withthe plate/implant combination or the expandable interbody spacer 600, asthe case may be, secured to and under the control of insertion system700 which is tethered to the either the first or second retractor blade200 a, 200 b. Attaching the plate/implant combination or the expandableinterbody spacer 600 to bone while attached to and under the control ofthe insertion system 700, which is in turn secured relative to eitherthe first or second retractor blade 200 a, 200 b which is secured to oneor both of the adjacent vertebrae, assures that the position of thespacer 500 or the expandable interbody spacer 600 does not shift as thebone screws are inserted and driven into bone. In the case of insertionof expandable interbody spacer 600, the implant advantageously may beinserted into the disc space and secured to the vertebrae by bone screwswith the ALL intact. It is common to release the ALL prior to insertingand securing an expandable interbody spacer 600, but releasing the ALLprior to inserting and securing the expandable interbody spacer 600 maymobilize the vertebrae and increase the likelihood that the position ofthe expandable interbody spacer 600 or bone screws will shift away fromthe desired position during insertion. Since the expandable interbodyspacer 600 may be inserted in an unexpanded condition and expanded afterbone screws are inserted through apertures 610 a, 612 a into bone tosecure the expandable interbody spacer 600 relative to the vertebrae,the ALL may be released after the expandable interbody spacer 600 hasbeen secured in place with bone screws, thereby assuring that theexpandable interbody spacer 600 and/or bone screw position doesn't shiftduring insertion due to mobilization caused by release of the ALL. Afterthe ALL is released with the expandable interbody spacer 600 secured inplace, the expandable interbody spacer 600 may be expanded to adjust forlordosis. It is contemplated that the ALL may be released by cutting theALL or it may be released upon expansion of the expandable interbodyspacer 600.

Referring now to FIG. 8A, an expander is shown for rotatably engagingand expanding an expandable interbody spacer 600 (FIGS. 5A-5G), theexpander designated generally 800. The expander 800 has a handle 802, ashaft having a first section 804 a and a second section 804 b extendingdistally from the handle 802, and a blade 808 extending distally from adistal portion of the second section 804 b of the shaft. The first andsecond sections 804 a, 804 b are removably coupled by a locking collar806 coupled to the first section 804 a of the shaft.

The second section 804 b of the shaft has the blade 808 extendingdistally therefrom. The blade 808 has a rounded portion 808 a and anedge 808 b extending outward from the rounded portion 808 a.Additionally, the blade 808 may taper from the rounded portion 808 atoward the edge 808 b such that the edge 808 b has a thinnercross-section than the rounded portion 808 a.

It will be understood that various modifications may be made to theembodiments of the presently disclosed sensing device. Specifically,while use of the insertion system 700, the insertion system 700, and theexpandable interbody spacer 600 have been describe in detail inconnection with the use of the retractor 100, it will be understood thatthe devices may be used in connection with devices known in the art. Forexample, the aforementioned devices may be used with known retractors orother known techniques or methods to deliver the spacer 500, orexpandable interbody spacer 600, to the target site. Additionally, thespacer 500 and expandable interbody spacer 600 may be used with one ormore insertion systems and/or retractors during surgical procedures.Therefore, the above description should not be construed as limiting,but merely as exemplifications of embodiments. Those skilled in the artwill envision other modifications within the scope and the spirit of thepresent disclosure.

What is claimed is:
 1. An expandable interbody spacer, comprising: afirst body portion pivotably coupled to a second body portion, whereineach of the first body portion and the second body portion defines abone screw mount offset from a plane transverse to a pivot axis definedby a rod, and wherein each bone screw mount is along a second axisperpendicular to the plane when the expandable interbody spacer is in aclosed configuration; a pawl beam rotatably coupled to the second bodyportion; and a plurality of teeth extending from an engagement wall ofthe first body portion, the plurality of teeth configured to engage thepawl beam, wherein transitioning the expandable interbody spacer fromthe closed configuration to an open configuration causes the pawl beamto engage the plurality of teeth to prevent the expandable interbodyspacer from transitioning towards the closed configuration.
 2. Theexpandable interbody spacer of claim 1, wherein each bone screw mountincludes a bone screw aperture.
 3. The expandable interbody spacer ofclaim 2, each bone screw aperture is angled to direct a screw insertedtherethrough into a first vertebrae or a second vertebrae.
 4. Theexpandable interbody spacer of claim 1, wherein the pawl beam isrotatably coupled to the second body portion via a pawl rod.
 5. Theexpandable interbody spacer of claim 1, wherein when the expandableinterbody spacer is in the closed configuration the first and secondbody portions define a gap.
 6. The expandable interbody spacer of claim5, wherein the gap is configured to receive an expander.
 7. Theexpandable interbody spacer of claim 5, wherein when an expander isinserted into the gap and rotated, the first body portion rotatesrelative to the second body portion such that the plurality of teethextending from the engagement wall engage the pawl beam.
 8. Theexpandable interbody spacer of claim 1, wherein the second axis isoffset from a central portion of the expandable interbody spacer.
 9. Theexpandable interbody spacer of claim 1, wherein each of the first bodyportion and the second body portion include an upper surface having aplurality of micro-apertures configured to inhibit movement of theexpandable interbody spacer relative to adjacent vertebrae when theexpandable interbody spacer is in the open configuration.
 10. Theexpandable interbody spacer of claim 1, wherein the rod pivotablycouples the first and second body portions.
 11. A method of performing asurgical procedure, the method comprising: positioning an expandableinterbody spacer between a first vertebrae and a second vertebrae;inserting a first bone screw through a first body portion of theexpandable interbody spacer and into the first vertebrae; inserting asecond bone screw through a second body portion of the expandableinterbody spacer and into the second vertebrae; inserting an expanderbetween the first and second body portions; rotating the expander in afirst direction, after inserting the first bone screw and the secondbone screw to cause the expandable interbody spacer to transition from aclosed configuration to an open configuration.
 12. The method of claim11, wherein moving the first body portion and the second body portionaway from one another comprises engaging the pawl beam and the pluralityof teeth.
 13. The method of claim 12, wherein the pawl beam is rotatablycoupled to the second body portion via a pawl rod.
 14. The method ofclaim 12, wherein the engagement of the pawl beam and the plurality ofteeth prevent the interbody spacer from transitioning towards a closedconfiguration.
 15. The method of claim 11, further comprising passivelyexpanding the interbody spacer based on the positioning of the first andsecond vertebrae.
 16. The method of claim 11, wherein: inserting thefirst bone screw through the first body portion further includesinserting the first bone screw through a first bone screw mount,inserting the second bone screw through the second body portion furtherincludes inserting the second bone screw through the second bone screwmount, and the first bone screw mount and the second bone screw mountare offset from a plane transverse to a pivot axis.
 17. The method ofclaim 16, wherein each bone screw mount includes a bone screw aperture.18. The method of 17, wherein each bone screw aperture is angled suchthat when the first bone screw or second bone screw is inserted throughthe bone screw apertures, the bone screw is inserted into the first andsecond vertebrae.
 19. The method of 11, further comprising passivelyexpanding the expandable interbody spacer based on a position of apatient.
 20. A method of performing a surgical procedure, the methodcomprising: positioning an expandable interbody spacer between a firstvertebrae and a second vertebrae; inserting a first bone screw through afirst body portion of the expandable interbody spacer and into the firstvertebrae; inserting a second bone screw through a second body portionof the expandable interbody spacer and into the second vertebrae; andmoving the first vertebrae away from the second vertebrae such that aportion of the first body portion moves away from a portion of thesecond body portion.